TOPIC: Pee Hole modifications on 1960s Mercury – pictures

I had a problem with the pee hole or tell tale in my 1964 Mercury 500 50HP.

This form was VERY helpful with information on this topic. So here are the basics pulled for many old posts on this and other forums. None of this is original. I am just summarizing and combining what others have suggested.

Most of you expects on this forum have already dealt with this issue. This is meant for the new person like myself trying to figure this all out.

The pee hole is located on the left rear of the lower cowl on these mid 1960s Mercury motors. There is no hose to the hole. The water comes right out of the engine block and there lies part of the problem. The hole in the block is very small and it easily and frequently gets clogged. No matter how many times you push in a wire up in it or shoot a steam from a pressure washer, it is going to clog up again. Your day boating gets ruined when the hole stops peeing water and you have to figure out did the impeller just go or is the hole clogged AGAIN,

The solution is to create a secondary system to check the water flow. On the top of the engine block is a 1/8 pipe fitting plug. You have to remove the top cover and starter to get to it. Unscrew the plug and screw in a 1/8 elbow with a ¼ compression fitting on the other end. (Some pipe dope on the 1/8 fitting is reasonable.) Cut a ¼ inch copper pipe to fit across the top of the engine block and attach a ¼ compression elbow fitting to run the pipe down the right side of the engine. (My boat is a right hand drives, so this allows me to see the stream from the drivers side.) Drill a small hole in the bottom of the lower cowling for the copper pipe to exit. I crimped the end slightly and angled the stream to make it more visible. This takes about 15 minutes and cost $7.00 in parts.

Yes, for the purest we made a terrible alteration to an antique engine. Some have suggested that this may actually improve the water circulation in the engine and make engine cooling more effective. The idea of a air or stream bubble at the top restricting water flow seems credible. All I know if that I can tell definitively that water is circulation through my engine. Another suggestion was to take a rubber hose and bring the stream all the way to the drivers position. A pressure gauge could be attached or just shoot it over the side. The drive will certainly see that stream !!

Trying to add pictures.....

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nice but i would use a rubber hose. will flex and not break.